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DFT calculations were performed to study the effect on energetic and magnetic stability when clusters with up to 24 lithium atoms were doped with one and two atoms of yttrium.

Bismuth adsorbed on the MBTS-modified surface facilitates the mass and charge transfer necessary for copper's selective sensing.

The study of γ-aminobutyric acid B receptor (GABAB ) activation is of great interest for several brain disorders. The search of new GABAB receptor agonists has been carried out by many research groups. As a result, Baclofen has become the prototypical GABAB receptor agonist. However, several attempts have been made to modify its structure to generate derivatives with improved activity. In this work, we carried out a theoretical and computational study for a wide range of GABAB receptor agonists reported in the literature. Molecular docking and QSAR techniques were combined by using the interaction energies of the agonists with the key residues of GABAB receptor, as molecular descriptors for the QSAR construction. The resulting mathematical model suggests that the activity of GABAB receptor agonists is influenced by three factors: their shape and molecular size (PW5 and PJI2), their constitutional features (ELUMO and T(N…O)) and the energy interaction with GABAB receptor (ETRP278 ). This model was validated by the QUIK, REDUNDANCY and OVERFITTING rules, and its predicted ability was tasted by the QLOO , QASYM , R 0 2 and r m 2 rules. Finally, six new compounds are proposed (35-40) with high potential to be used as GABAB receptor agonists.

With the idea of proposing solid state systems that have a high storage capacity of molecular hydrogen, a density functional theory study of magnesium oxide (MgO)n clusters (n = 1-10) was carried out. Hydrogen-magnesium oxide systems presented adsorption energy values in accordance with the previously reported studies of physisorption processes; additionally negative values of ΔGads were found describing adsorption as a favorable process. Here, the (MgO)7 cluster presented the highest adsorption energy. The storage capacity by weight of the magnesium oxide clusters was greater than the recommended percentage (7.5%) by the U.S. Department of Energy. QTAIM analysis and non-covalent index plots highlighted the weak nature of the interaction between the MgO clusters and hydrogen molecules, and the fundamental role of the Mg-O bonds' polarity in the systems' storage capacity.

New tributyl-, dibutyl- and diphenyl-tin(IV) complexes derived from ibuprofen and cinnamic acids were synthesized. All compounds were structurally characterized by FT-IR, multinuclear 1H, 13C, 19F and 119Sn NMR and corroborated by 2D spectra. The NMR data in CDCl3 revealed several hexacoordinated compounds with octahedral geometry. Moreover, in DMSO-d6 some of these complexes switched to heptacoordination with a pentagonal-bipyramidal geometry due to the inclusion of a solvent's molecule; their 119Sn signals moved up field by around 58 ppm compared to their chemical shifts in non-coordinated solvent CDCl3. The structural results were supported by Density Functional Theory (DFT) computational calculations. In addition, a docking study was performed to evaluate the ability of ligands to interact within the active site of cyclooxygenases (COX-1 and COX-2). Docking results showed a possible binding of stannoxanes theoretically more selective towards COX-2 than ibuprofen.

A study was carried out to determine the structural, energetic, and magnetic properties of lithium clusters doped with yttrium, including Born − Oppenheimer molecular dynamics under the Density Functional Theory framework. The study considered the ZORA model for the scalar relativistic effects due to the presence of the yttrium atom. The Li12Y system was identified as a new superatom with icosahedral geometry, high magnetic moment, and exchange splitting. The interactions of the sp-Li orbitals with the 4d-Y orbitals are fundamental to understand the effects on the studied properties. The spin density was concentrated over the yttrium atom regardless of the size of the cluster. Furthermore, the energetic integrity of the Li12Y is preserved in the (Li12Y)2 dimer, attesting to its potential as a magnetic building block for nanostructured materials. Additionally, the effect of temperature on the magnetic moment in the context of classical Boltzmann distribution was explored, finding a dependence between magnetic properties and temperature.

Cytotoxic effects of cannabidiol (CBD) and tamoxifen (TAM) have been observed in several cancer types. We have recently shown that CBD primarily targets mitochondria, inducing a stable mitochondrial permeability transition pore (mPTP) and, consequently, the death of acute lymphoblastic leukemia (T-ALL) cells. Mitochondria have also been documented among cellular targets for the TAM action. In the present study we have demonstrated a synergistic cytotoxic effect of TAM and CBD against T-ALL cells. By measuring the mitochondrial membrane potential (ΔΨm), mitochondrial calcium ([Ca2+]m) and protein-ligand docking analysis we determined that TAM targets cyclophilin D (CypD) to inhibit mPTP formation. This results in a sustained [Ca2+]m overload upon the consequent CBD administration. Thus, TAM acting on CypD sensitizes T-ALL to mitocans such as CBD by altering the mitochondrial Ca2+ homeostasis.

COX-2 is a widely studied biological target, since its activity is directly related to the inflammation response. The design of COX-2 selective inhibitors is an ongoing topic in drug design. We performed a quantitative structure–activity relationship and docking studies over a series of benzenesulfonamide derivatives on their inhibition towards COX-1 and COX-2, in order to rationalize their selectivity towards COX-2. Constitutional, topological and molecular property descriptors for the QSAR models and molecular docking calculations were employed. The mathematical model highlighted that lipophilic character and size are the most important features for COX-2 inhibition by benzenesulfonamides. A second QSAR model revealed that the dipole moment, the number of hydrogen bond donors and lipophilicity descriptors of benzenesulfonamides are crucial for their binding to COX-1. Moreover, artificial neural networks were employed to improve the prediction power of the COX-1 inhibition QSAR model. In this sense, we proposed new selective potential inhibitors by introducing different halogens into the benzenesulfonamide scaffold, improving their interactions with key residues of COX-2.

Annona purpurea, known in Mexico as “cabeza de negro” or “ilama”, belongs to the Annonaceae family. Its roots are employed in folk medicine in several regions of Mexico. Taking that information into account, a chemical and biological analysis of the components present in the roots of this species was proposed. Our results demonstrated that the dichloromethane (DCM) extract was exclusively constituted by a mixture of five new acetogenins named annopurpuricins A–E (1–5). These compounds have an aliphatic chain of 37 carbons with a terminal α,β unsaturated γ-lactone. Compounds 1 and 2 belong to the adjacent bis-THF (tetrahydrofuran) α-monohydroxylated type, while compounds 3 and 4 belong to the adjacent bis-THF α,α’-dihydroxylated type, only compound 5 possesses a bis-epoxide system. Complete structure analysis was carried out by spectroscopy and chemical methods. All compounds were evaluated for their antiproliferative activity on three human tumor cell lines (MSTO-211H, HeLa and HepG2). Compounds 1–4 inhibited significantly the growth of HeLa and HepG2 cells, showing GI50 values in the low/subnanomolar range, while 5 was completely ineffective under the tested conditions. The investigation of the mechanism of action responsible for cytotoxicity revealed for the most interesting compound 1 the ability to block the complex I activity on isolated rat liver mitochondria (RLM).

The study of γ-aminobutyric acid B receptor (GABA

Annona purpurea, known in Mexico as “cabeza de negro” or “ilama”, belongs to the Annonaceae family. Its roots are employed in folk medicine in several regions of Mexico. Taking that information into account, a chemical and biological analysis of the components present in the roots of this species was proposed. Our results demonstrated that the dichloromethane (DCM) extract was exclusively constituted by a mixture of five new acetogenins named annopurpuricins A–E (1–5). These compounds have an aliphatic chain of 37 carbons with a terminal α,β unsaturated γ-lactone. Compounds 1 and 2 belong to the adjacent bis-THF (tetrahydrofuran) α-monohydroxylated type, while compounds 3 and 4 belong to the adjacent bis-THF α,α’-dihydroxylated type; only compound 5 possesses a bis-epoxide system. Complete structure analysis was carried out by spectroscopy and chemical methods. All compounds were evaluated for their antiproliferative activity on three human tumor cell lines (MSTO-211H, HeLa and HepG2). Compounds 1–4 inhibited significantly the growth of HeLa and HepG2 cells, showing GI50 values in the low/subnanomolar range, while 5 was completely ineffective under the tested conditions. The investigation of the mechanism of action responsible for cytotoxicity revealed for the most interesting compound 1 the ability to block the complex I activity on isolated rat liver mitochondria (RLM).

In this work a novel selective sensor for copper based on a carbon paste electrode modified with 2-mercaptobezothiazole (CPE-MBT) using square wave anodic stripping voltammetry (SWASV) is presented. Parameters such as pH, potential and deposition time, amount of bismuth, etc. were optimized to have a selective and quantitative detection of copper, even in the presence of other metals and common interferences. The results showed a detection limit of 0.71 ppm and a quantification limit of 83.177 µA/cm2 with good repeatability and reproducibility. Additionally, the sensor was successfully applied to the analysis of water samples. Density functional theory and atoms in molecules calculations agree with the experimental results, providing insights on the modified electrode’s surface.

Benzyne from trichlorobenzene has been employed for Diels-Alder cycloaddition with dienes, such as furan and 2,5-dimethylfuran, to synthesized novel dichloro-1,4-dihydro-1,4-epoxynaphtalene derivatives. These compounds have not been characterized or reported. The 1H NMR spectra of cycloadducts were fine resolved, and unambiguous proton chemical shift assignments were based on the multiplicity pattern of proton resonance and confirmed by 2D NMR from COSY, HSQC, and HMBC data. Computational calculations were performed for a crystal of 5,6-dichloro-1,4-dihydro-1,4-epoxynaphtalene. This compound crystallized as a monoclinic system in the space group C2/c with eight molecules in the unit cell, a = 18.313 (6) A, b = 8.128 (3) A, c = 14.157 (4) A, β = 119.942 (9)°, V = 1825.9 (10) A3, Z = 8.

The structures of thioethers I-III and the new amidic compounds 1(a-f)-3(a-f) derived from 2-mercaptobenzimidazole (MBZ) and cinnamic acids were confirmed by NMR and elemental analysis. Antioxidant activity was evaluated by 1,1-diphenyl-2-picrylhydrazyl (DPPH●) radical scavenging assay and 2,2-azinobis (3-ethyl benzothiazoline-6-sulfonic acid) ABTS●+ radical cation decolorization method. Besides, donor-acceptor maps (DAM) and electrophilicity were calculated using DFT/B3LYP method with a 6-311G(d,p) basis set. MBZ, I-III and (1a-3a) compounds showed higher activity in in vitro antioxidant assays, confirming with in silico studies that they are the best candidates. The findings found in antiradical activity suggest that these compounds could be promising in the development of new antitumor and antimicrobial agents. QSAR Molecular properties and topological descriptors of the synthesized compounds 1(a-f)-3(a-f) were calculated. The QSAR model indicates that the size and molecular shape are relevant for the antiradical activity for this family of compounds.

The compound 2-aryl-2,3-dihydro-4H- [1,3]thiazino[3,2-a]benzimidazol-4-one (C16H12N2OS) (III) was synthesized. The compound crystallized in a monoclinic crystal system with P21/c space group as revealed by mono-crystal X-ray diffraction. The X-ray analysis and density functional theory complementary calculations showed that noncovalent C–H···π interactions between the benzimidazole system and the thiazine ring form a dimerization along the direction of the b axes, additionally π···π interactions were found between the benzene rings. The C12, in the thiazine ring, has a distortion angle (41.69°) respect to the plane of benzimidazole. The intermolecular interactions in the crystal structure were quantified and analyzed using Hirshfeld surface analysis. The predominant interaction within the crystalline structure was found to be H⋯H interaction. On the other hand, antioxidant activity of the C16H12N2OS system was studied using the DPPH and ABTS + assay. Using the energy profile for the reaction of DPPH with III it was demonstrated that the antioxidant activity is carried out through HAT (H12) mechanism where conjugation of the radical can occur between the C12 of the thiazine ring and the aromatic ring, this was confirmed by a H function calculation. The importance of this study focuses on the promising range of biological activities and molecular characteristics of the synthesized compound (III).

Density functional theory calculations based on magnetic and energetic stability criteria were performed to study a series of yttrium-doped lithium neutral clusters. A relativistic approximation was employed to properly describe the energy and multiplicity of the given clusters’ fundamental states. The interaction of the 4d-Y atomic orbitals with the sp-Li states had an important role in the magnetic and energetic behavior of the selected systems. The spin density was concentrated over the yttrium atom regardless of the size of the cluster. Li7Y is a new stable superatom due to its enhanced magnetic properties.

A series of helicoid metallocenes structures were studied in silico under the DFT framework. Their reactivity was explored by the dual Fukui function. An energy decomposition analysis was performed in order to gain insight into the interaction between the helix-like ligand and the metallic nuclei. Helical cobaltocene was highlighted as an interesting synthetic target through its peculiar response to ionization as well as its interaction and preparation energies.

There are many chronic diseases related with inflammation. The chronic inflammation can produce other problems as cancer. Therefore, it is necessary to design drugs with better anti-inflammatory activity than those in the clinic. Likewise, these could be used in chronic treatments with minimum adverse effects. The amide or ester functionality in combination with the insertion of a silyl alkyl moiety is able to improve some drug properties. In this context, the evaluation of a group of silicon containing ibuprofen derivatives (SCIDs) as antioxidants and anti-inflammatory agents is reported. Antioxidant activity was evaluated by the 2,2-Diphenyl-1-picrylhydrazyl (DPPH⨪), 2,2'-Azino-bis(3-ethylbenzothiazoline-6-sulfonic) acid (ABTS•+) and the Fe(II) chelating ability methods. The anti-inflammatory activity was determined by using the carrageenan induced rat paw edema. The gastrotoxic profile of the SCIDs that displayed significant anti-inflammatory activity was determined by the indomethacin induced ulceration method. The SCIDs performed better than ibuprofen as chelating agents for Fe(II) and as scavengers for the free radicals DPPH• and ABTS•+. On the anti-inflammatory test, compound 4a inhibited the edema up to 87%, while 4d &10b achieved significant inflammation inhibition at a lower effective dose 50 (ED50) than ibuprofen´s. None of the SCIDs endowed with anti-inflammatory activity, showed significant gastrotoxic effects with respect to those displayed by ibuprofen. Based on the experimental results and aided by the theoretical docking approach, it was possible to rationalize how the SCIDs may bind to cyclooxygenase isoforms and helped to explain their reduced gastrotoxicity. The evaluated effects were improved in SCIDs with respect to ibuprofen.

A Quantitative Structure-Activity Relationship (QSAR) of coumarins by genetic algorithms employing physicochemical, topological, lipophilic and electronic descriptors was performed. We have used experimental antioxidant activities of specific coumarin derivatives against the DPPH· radical molecule. Molecular descriptors such as Randic Path/Walk, hydrophilic factor and chemical hardness were selected to propose a mathematical model. We obtained a linear correlation with R2 = 96.65 and Q 2 = 93.14 values. The evaluation of the predictive ability of the model was performed by applying the Q 2 , $\hat r^2 $ and Δr 2 methods. Fukui functions were calculated here for coumarin derivatives in order to delve into the mechanics by which they work as primary antioxidants. We also investigated xanthine oxidase inhibition with these coumarins by molecular docking. Our results show that hydrophobic, electrostatic and hydrogen bond interactions are crucial in the inhibition of xanthine oxidase by coumarins.

Here we explore in the Density Functional Theory (DFT) framework the antiradical activity of picolinic ( PA ), nicotinic ( NA ) and isonicotinic ( INA ) acids and a group of derivative stannoxanes of the type RC(O)OSnX 3 . Using the single charge transfer model proposed by Gazquez et al. (electrodonating ω − and electroaccepting ω + powers), a Donor Acceptor Map (DAM) was employed to classify them as good or bad antiradicals. In the case of acids, an antiradical activity behavior was measured for each bond position of the –COOH functional group at the pyridine ring. For esters, antiradical activity was calculated considering three types of ligands: n -butyl, phenyl and the above acids. Esters showed a better antiradical behavior as electron donors than their corresponding acids. Two esters derived from picolinic acid showed a good donor index ( R d ), which was closed to R d of vitamin C, all above in their neutral form. In this assessment, the analytic Fukui function isosurface f − was included in order to determinate those regions of our molecules where it is most likely to occur the interaction with a free radical. The Fukui function f − was located mainly at the N atom of the pyridine ring for the three acids and most of the esters.

The synthesis and characterization of six new O-cholesteryl-dithiophosphonates containing thio-metalloheterocycles of As(III) and Sb(III); (CH2S)2As[S2P(cholesteryl)(4-MeOC6H5)] (2), (CH2S)2Sb[S2P(cholesteryl)(4-MeOC6H5)] (3), O(CH2CH2S)2As[S2P(cholesteryl)(4-MeOC6H5)] (4), O(CH2CH2S)2Sb[S2P(cholesteryl)(4-MeOC6H5)] (5), S(CH2CH2S)2As [S2P(cholesteryl)(4-MeOC6H5)] (6), and S(CH2CH2S)2Sb[S2P(cholesteryl)(4-MeOC6H5)] (7) are reported. 2–7 have been prepared from the reaction between the triethylammonium salt of O-3β-cholest-5-en-3-yl (4-methoxyphenyl) dithiophosphonate (1) and five and eight membered chloro-metalloheterocycles of As(III) and Sb(III). The obtained compounds have been characterized by elemental analyses, IR and NMR (1H, 13C, and 31P) spectroscopy. The 31P NMR data suggest that the dithiophosphonate ligand presents, in solution, a bidentate coordination. The structures of 3 and 4 were determined by X-ray single crystal analysis, that correspond to the first examples of such determinations in Group 15 dithiophosphonates, showing an anisobidentate coordination mode of the dithiophosphonate moiety. Sb(III) and As(III) in compounds 3 and 4 present tetracoordination and pentacoordination, respectively. The pentacoordination in 4 is achieved through a 1,5 transannular As⋯O interaction. Antibacterial assays were performed and the activity was correlated with the electronic distribution and molecular shape, employing their geometrical structures, Mulliken partial charges, dipole moments and Molecular Electrostatic Potential maps from DFT calculations.

First principles electronic structure calculations guided by energetic and magnetic principles of stability are conducted to predict and investigate a series of yttrium doped alkali clusters with a compact icosahedral structure and a large spin magnetic moment. The energetic stability of the YM12 (M = K, Rb and Cs) species lies on the nature of their electronic configuration and is a result of the controlled hybridization of the 4d-Y levels with the sp-alkali states. Further, the integrity of the YK12 is found to be conserved in a (YK12)2 dimer attesting for its potential as a magnetic building block for nanostructure materials.

In this work we define a shape entropy by calculating the Shannon's entropy of the shape function. This shape entropy and its linear response to the change in the total number of electrons of the molecule are explored as descriptors of bonding properties. Calculations on selected molecular systems were performed. According to these, shape entropy properly describes electron delocalization while its linear response to ionization predicts changes in bonding patterns. The derivative of the shape entropy proposed turned out to be fully determined by the shape function and the Fukui function.

β-Fructosidase, a glycoside hydrolase of a biotechnologically important strain, was studied for its biochemical, physicochemical, and three-dimensional structure characteristics. This enzyme was heterologously expressed in Escherichia coli as a C-terminal His-tagged protein (SacB). β-Fructosidase catalyzes the cleavage of glycoside bonds toward certain carbohydrates with β-fructofuranosyl linkages; however, SacB exhibited selectivity toward sucrose and an optimum activity at pH 6.0–6.5 and 37 °C. In such optimum enzymatic activity conditions, the SacB was commonly observed as a monodisperse protein by dynamic light scattering (DLS). As β-fructosidase belongs to glycoside hydrolase family 32 (GH32), a β-sandwich and a five-bladed β-propeller domain are typical predicted folds in its structure. Docking and molecular dynamic simulations revealed for the first time a funnel-like channel perfectly exposed in the β-propeller domain of the Lactobacillus plantarum β-fructosidase (this allows the interaction between its entire catalytic triad and substrates that are larger than sucrose). In contrast, SacB showed a closed central tunnel collaterally induced by its His-tag.

N-heterocyclic norbornene Dicarboximides were synthesized by reacting the exo-norbornene-5,6-dicarboxylic anhydride with 2-, 3-, and 4-aminopyridine. The amides resulting from 3 and 4-aminopyridine derivatives were converted into the corresponding betaines via Menshutkin reaction using ethyl-bromoacetate. The chemical structures of the obtained products were confirmed by FT-IR and 1 H and 13 C NMR spectroscopy, EA and MS as well as by calculation of 1 H and 13 C NMR chemical shifts using the GIAO method (PW91/6-311G++ (3df, 3pd) approximation by GAUSSIAN and PW91/IGLO-III approximation by deMon2k).

Fischer base derivatives are widely used as precursor in the formation of different chemical switches. Besides, in the presence of acyl chlorides, indole enaminoketone derivatives can be prepared. 2,3-Dihydro-2-(R-phenylacylidene)-1,3,3-trimethyl-1H-indole, R = 4-NO2, 3,5-(NO2)2 and 4-OCH3, have been characterized previously but only by 1H NMR, thus further characterization was performed by FTIR, 13C NMR and when suitable crystals were obtained by single crystal X-ray diffraction analyses. The structures of the three molecules were additionally analyzed by DFT methods, B3LYP and PW91 functionals, using 6-311G(d,p) basis set. The optimized structures obtained were compared with those determined by crystallographic data. The probable assignments of the anharmonic experimental solid state vibrational frequencies for these molecules have been also made based on the calculated harmonic frequencies in vacuum at the same level of theory for the optimized structures. Correlations between experimental chemical shifts and GIAO calculated magnetic isotropic shielding constants with B3LYP and PW91 functionals using the 6-311++G(3df,3pd) basis set are also reported.

The molecular and electronic structures of a series of 2-[(R-phenyl)amine]-1,4-naphthalenediones (R = m-Me, p-Me, m-Et, p-CF3, p-Hex, p-Et, m-F, m-Cl, p-OMe, p-COMe, p-Bu, m-COOH, p-Cl, p-COOH, p-Br, m-NO2, m-CN, and p-NO2) and their anions are investigated in the framework of density functional theory. The calculations are of all-electron type using a double zeta valence polarization basis set optimized for density functional theory methods. The theoretical study shows that all compounds are nonplanar. The nonplanarity can be rationalized in terms of occupied π orbitals. A linear correlation between the measured half-wave potentials and the calculated gas-phase electron affinities is found. It holds for local as well as generalized gradient corrected functionals. Structural parameters, harmonic vibrational frequencies, and adiabatic and vertical electron affinities as well as orbital and spin density plots of the studied compounds are presented.

This work presents a study of the structure of neutral and anionic copper cluster nonamers with density functional theory calculations. The structure optimization and frequency analysis were performed at the local density approximation (LDA) level of theory with the exchange correlation functional by Vosko, Wilk, and Nusair (VWN). Improved calculations for the structure stability were based on the generalized gradient approximation (GGA) where the exchange correlation functional of Perdew and Wang (PW) was used. For both neutral and anionic clusters, new isomers are found that are more stable than those already presented in the literature. Adiabatic and vertical electron affinities are calculated and compared with the experimental value reported for Cu9. The calculated values are in good agreement with the available experimental data. An analysis of the most relevant molecular orbitals (MOs) of the low-lying neutral and anionic copper cluster nonamers is reported, too.

Nineteen 2-[(R-phenyl)amine]-1,4-naphthalendione derivatives (PAN) were tested on spinach thylakoids for their activity as electron acceptors. These molecules act as photosystem I electron acceptors in the micromolar range. AC 50 values varied from 5 nM to 24 μM. QSAR analysis revealed a linear correlation of the m -PAN derivative log [1/AC 50 ] with the energy difference of the LUMO and HOMO orbitals. The biological activity of p -PAN derivatives correlates linearly with structural parameters. Electron affinity is being the most important. The half wave I potential values ( E 1/2 ) of PAN compounds (from −213 to −569 mV vs. NHE) match with the mid-point potentials of the A 0 to F X niche of PSI electron transport carriers. The log P values of PAN derivatives were 3.35 and 3.88, indicating that they are hydrophobic compounds. Therefore PAN compounds accept electrons at the hydrophobic A 0 to F X niche of PSI.

A scheme for the σ-π separation of the total energy at the Kohn-Sham density functional theory (KS-DFT) level is presented. Several six-, five- and four-membered ring systems were investigated with this scheme. Normal mode coordinate distortions were investigated. The character of the σ and the π energy with respect to bond equalization and bond alternation was studied. The influence of the core–core repulsion energy term on the results is discussed.

In this work, a graphical tool for postdeprotonation analysis of molecular systems is presented. This tool was applied to a series of molecules to distinguish the information given by its resulting graphics. The outcome identified the h function sensitivity toward electron density rearrangement, being able to recognize bond cleavage and increments in π electron population through simple visual analysis.

The synthesis and structural characterization of novel amine-borane adducts of ibuprofen derivatives are presented. The changes of the electron density on the carbonyl and pyridine ring after formation of N→BH3, N→BF3, and N-CH3+ have been confirmed by 1H, 11B, 13C, and 19F NMR, further supported by homonuclear and heteronuclear correlations. Moreover, electrostatic interactions —H+···−F and the nonclassical H+···−H— were identified by NMR spectra. The analysis of the resulting molecular structures offered insights on the 2-aminopyridine N→B adducts. The N→BH3 adduct formed a single molecular arrangement, both in C6D6 and CDCl3. The same behavior was observed for the N→BF3 adduct in CDCl3. However, two conformers of this adduct were detected in C6D6. All adduct geometries were corroborated by density functional theory computational calculations.

Hyperjovinol-A ((2-methyl-1-(2,4,6-trihydroxy-3-(3-hydroxy-3,7-dimethyloct-6-enyl)phen yl)propan-1-one) is an acylated phloroglucinol isolated from Hypericum Jovis and exhibiting good antioxidant activity. The study investigates the compound’s antiradical ability on the basis of the electron-donor and electron-acceptor abilities of its conformers, deriving donor and acceptor indexes and mapping them in terms of donor-acceptor maps (DAM). The DAMs of vitamins C and E and of carotene astaxantine are used as comparison references. Calculations were performed at the DFT/BPW91/6-311+G(d,p) level, with optimizations on fully relaxed geometries to obtain the conformers of the neutral molecule in vacuo, and single point calculations to obtain the energies of the cationic and anionic species in vacuo and of the neutral, cationic, and anionic species in water, ethanol, and pentylethanoate. The calculations in solution utilized the polarizable continuum model (PCM). The results indicate that hyperjovinol-A may have better antiradical activity than vitamin C. This is in agreement with experimental results, showing that the antioxidant activity of hyperjovinol-A is comparable with that of the best drugs currently in clinical use. The activity is maintained in solution. The Fukui function f(·) was also calculated for all the conformers of hyperjovinol-A, to identify the regions of highest reactivity.

Here, we address the problem of stabilizing a new helicoid ferrocene. Of course, to obtain a helical complex, it is essential to design suitable organic ligands. The ligands should possess the correct symmetry to match the geometrical requirement of the metal center. We propose in silico a beautiful helix that consists of one polycyclic hydrocarbon composed of 10 fused cyclopentadiene rings bound on opposite sides of an iron atom. The nature of the metal-ligand interactions between Fe(2+) and the ligand was investigated with energy decomposition analysis. Our results provide strong evidence for the viability of the hitherto unknown helicoid ferrocene as a target for synthesis.

This work presents an all-electron density functional theory implementation of the separation of sigma and pi energies. On the basis of the separation of the electronic density, rho, into sigma and pi parts, an ansatz for the separation of the exchange-correlation energy is proposed. The behavior of the sigma and pi energy parts in benzene is investigated under different distortions. The effect of local and nonlocal functionals on the separation of the exchange-correlation energy is studied, too.

The synthesis and characterisation of new silicon-containing amides and esters derived from ibuprofen is reported. These compounds were tested against nuclear transcription factor κβ (NF-κβ). Higher inhibition values than those of ibuprofen were achieved by the new amides 10a–10d; ester derivatives did not show inhibitory activity. The cytotoxicity of these new derivatives was screened; none of them displayed significant toxicity at the screened doses. A molecular docking calculation on IKKβ (an enzyme related to NF-κβ activation) was carried out and the results showed that the amides interact better than ibuprofen with key residues, which are important to the inhibition of IKKβ.

The in vitro antioxidant activities of eight 3-carboxycoumarin derivatives were assayed by the quantitative 1,1-diphenyl-2-picrylhydrazil (DPPH•) radical scavenging activity method. 3-Acetyl-6-hydroxy-2H-1-benzopyran-2-one (C1) and ethyl 6-hydroxy-2-oxo-2H-1-benzopyran-3-carboxylate (C2) presented the best radical-scavenging activity. A quantitative structure-activity relationship (QSAR) study was performed and correlated with the experimental DPPH• scavenging data. We used structural, geometrical, topological and quantum-chemical descriptors selected with Genetic Algorithms in order to determine which of these parameters are responsible of the observed DPPH• radical scavenging activity. We constructed a back propagation neural network with the hydrophilic factor (Hy) descriptor to generate an adequate architecture of neurons for the system description. The mathematical model showed a multiple determination coefficient of 0.9196 and a root mean squared error of 0.0851. Our results shows that the presence of hydroxyl groups on the ring structure of 3-carboxy-coumarins are correlated with the observed DPPH• radical scavenging activity effects.

Chemistry students have difficulty understanding molecular structures and their functions. To aide their comprehension, molecular visualization software has been developed to run on smart phones, but in order to positively influence learning it must have a high degree of usability (usability measures how software is used in terms of efficiency, efficacy and satisfaction). This paper describes a usability study of molecular visualization software running on a smart phone, where chemistry students analyzed molecular models. Results showed very good usability and 95% of students wanted to use it in further classes.

Introduction. Renin is the main rate-limiting enzyme in the renin—angiotensin—aldosterone system. Its gene, REN, is a candidate crucial factor in essential hypertension and cardiovascular disease. The aim of this study was to evaluate allele and haplotype distributions of REN polymorphisms, and to estimate normalised linkage disequilibrium ( D’) in Mexican and German populations. Materials and methods. Four groups were studied for the REN single nucleotide polymorphisms (SNPs) 1205C>T, 1303G>A, and 10607G>A, in population samples of Mexican Mestizo ( n = 86), Mexican Huichol ( n = 49), German ( n = 39), and individuals with hypertension diagnosis ( n = 66). Polymorphisms were detected by PCR—RFLP. Genotype, allele and haplotype frequencies were estimated. Results. SNP 1205C>T and 10607G>A allele and genotype distribution showed inter-group differences. The 1205T and 10607A allele showed a significance difference in hypertensive population. Haplotype analysis also showed some inter-group differences, especially in 1205C-1303G-10607G, 1205C-1303G-10607A and 1205T-1303G-10607G haplotypes. The segregation analysis disclosed complete linkage disequilibrium between 1205 and 1303 loci. Conclusion. These results provide an example of genetic diversity in related populations and illustrate the convenience of increasing the number of loci in associative studies between diseases and candidate genes.

For some years, Chemistry teachers have used scientific visualization software of molecular models in computing rooms and chemistry laboratories for educational purposes. However, its application in classrooms has been limited. This article describes the integration and use of computer programs for scientific molecular visualization in a traditional classroom. We consider that the improvement of technical aspects of their application and use (usability) has a direct effect on students' understanding of molecular structures (including students' extrinsic motivation), among other factors. Consequently, we developed a guide for the integration of hardware and software of molecular visualization for its use in the classroom.

This work presents an all-electron density functional theory implementation of the separation of sigma and pi energies. On the basis of the separation of the electronic density, rho, into sigma and pi parts, an ansatz for the separation of the exchange-correlation energy is proposed. The behavior of the sigma and pi energy parts in benzene is investigated under different distortions. The effect of local and nonlocal functionals on the separation of the exchange-correlation energy is studied, too.